Ascended Fanon: Scott Fischer wasn't given a superhero name during his time in the book, but prominent letter writer Charles J. Sperling decided that his name had to be "Blaze". Near the end of that era, the book's editor said that "Scott has adopted the name of Blaze, I think, but he hasn't officially used it."
Promoted Fanboy: The series has been out of the mainstream enough that many of the writers got the gig because they were fans of earlier series. Paul Kupperberg, Grant Morrison and John Byrne were all fans of the original Drake run, Rachel Pollack was a fan of the Morrison era (and had some letters published in the final Morrison issues, jokingly angling for the job, after she'd already gotten it), and Keith Giffen admitted he'd been trying to launch a Doom Patrol book for years.
Rachel Pollack had another arc in mind where a man finds an ATM, or Automatic Tarot Machine, that gives him abilities in line with the Tarot deck based on his PIN number, before Dorothy eventually uses it to turn him back into the Fool.
Joe Casey's Automatic Kafka started life as a Doom Patrol pitch.
Another rejected pitch that has come to light in the past few years was one by Scott Lobdell and Ilias Kyriazis, about an all-new Doom Patrol featuring stalwarts Cliff Steele and Gar Logan leading Tefé Holland, Platinum, Madame .44, Zatara and Bizarro, of all people. Kyriazis' blog also features concept art of Changeling, Tefé and Platinum combining into a platinum sword-wielding, tree-limbed green shark.